Allelopathy is the chemical warfare between corals - releasing terpenoid compounds that suppress competitors. Common in mixed reef tanks where soft corals (especially Sarcophyton) inhibit SPS growth.
Allelopathy is why mixed reef tanks fight each other. Aggressors: Sarcophyton (toadstool), Sinularia (finger leather), Cladiella (colt) release diterpenes that suppress SPS coral growth + zooxanthellae. Symptoms: SPS lose color, slow or stop growing, polyps stay retracted near offending soft corals. Mitigation: 1) carbon dosing constantly (replace every 2-3 weeks). 2) ozone (advanced). 3) heavy water changes. 4) physical separation - keep softies + SPS in separate tanks or opposite ends of long tanks. Reverse aggression: SPS like Acropora release nematocysts via sweeper tentacles + acid stings - dominate softies in close contact. Mixed reef solution: dedicate the tank to ONE coral type + accept the loss of variety. Or run aggressive carbon + frequent water changes if mixing.
Reviewed by the Fast Aquatics husbandry team · Updated May 2026
Allelopathy is the chemical warfare between corals - releasing terpenoid compounds that suppress competitors. Common in mixed reef tanks where soft corals (especially Sarcophyton) inhibit SPS growth. Allelopathy is why mixed reef tanks fight each other. Aggressors: Sarcophyton (toadstool), Sinularia (finger leather), Cladiella (colt) release diterpenes that suppress SPS coral growth + zooxanthellae. Symptoms: SPS lose color, slow or stop growing, polyps stay retracted near offending soft corals.
Full glossary · Q&A library · Calculators · Disease database